Equalizer for cable operated controls



July 27, 1948. w. H. D. BROUSE EQUALIZER FOR CABLE OPERATED CONTROLS 2 Sheets-Sheet 1 Filed May 21, 1945 Patented July 27, 1948 fumraos-mres EQUAI-HZER FOR CABLE OPERATED CONTROLS williamrHLlDyBrouse, Toronto, Ontario, Canada, assignoroto, Teleflex Limited, Toronto; Ontario;

Canada ApplicationtMayfll, 1945, Serial No. 5%,83?

(CLl i l-+501) z 4 Claims. 1

This invention relates to. the. operation of contoz ohviateavariations inwoperatingwload resulting 1 from: varying expansion-- and contraction of the operating cables and the conductor system: for

same due to temperature changes, thereby providi a system-with :maximumuoperat'mg: efficiency andtsmoothnesss Atfurtherobject issto provide acontrolrsystem which will? enable v a quick-r and accurate-1 adjustmenttfollowing therremoval. ofrtthe: cable-from its conductors foriperiodici inspection or=replacement A still Y further objectris tot providev complete automatic; compensation: of 1 th effect; of temperature chang-es;

l n The principal feature of theiinventlon consists in the-introduction into a cable-control operating systemtof a differentia-hgear-for: operating "same thereby providing} for: the application,- of: equal tension 5 and 1 compressiom loads-rte; thErCfiiblBcfil'ld permitting: compensation! -for"the-;i difference in length *I GIalJiOIIShiPwdHBT tO the effects; of: temperaturezchange. l In theaccompanying-drawings the a B of an;- aircraftzin "flight; 7 without tandrwithathe useeofi-theedifiercntial gear;

' Figure 7r is a graph' illustratingqthe: curves of operating loads .requiredcinrraisingzthe flaps at'KO of:an-aircraftzinafiight;iwithoutrand::withithealuse ofjthe difierentialzgean:

-In 2 th'edayout ,ofiflap cableiicontroh as applied to. an aircraft/masillustratediimFiguresal; andr2, thewcablezoperating gear-1 box lo whiclrtenclcsesva pairnot axiallm alignedwcable engaging g-ears j and 241151 arranged riraa;suitable"positionawailable-to thezoperatonathe gears and cablabe-ingpreferably of; the type known; as. filielerlexlt :inr which the 2 cable.2 of lflexible steel has woundjthereon auniformly: spaced spiral wire, 3" whichfitsjbetwe'en the peripheral teeth lvof tlieisaidugears, the periphery of whichis groovedto receiveandlgl ide theflexible cable.

The geometry of the, layout ,is that 'the cablez passes around the upper gear 510g the 'pair mounted in thebox Land .is conductedith'rough the curvedtube 6 tothe gear box liarranged on one winglof the aircraft and-,isyoperatively connected tothe screwjacktcf the flap operating unit 9 onsaidwing.

-.A. straight tube I 0 extending along the, rear wing sparconneots .the gear box 'lvwith thengear box ll arrangedvon theoppositewingiand'the cable-is operatively connectedwiththe. screw jack l 2 of the flap operatingvunitnli onth'e latter wmg.

A curvedtube M connectstthe, gearbox With the lower part ofthe. gearbox I andthehcable passescaroundlthe lower gear housedthereinr The terminal end of the cable passingraround theupper gear!) of thecontrol box! extendsdnto and'is housed in the tubewlfii. andlthecther terminal end, extending from the. lower? geartzkextends-into-and ishouseddin the tube.l.1,,thasaid tubes, 15 and I! merelyserving to enclose the free ends of the cable.

The gear box [is formedcfitwoisimilari sections 18- and I9 havingppeniinnen faces nesting againstta closing ring section 20 and the. three sections are clamped together by boltseextending throughrim holes 2 I. 1 Bushings-22am secured to the sections 18. and l 9 :with their, axes tangential to the toothed peripheriesiof, the-toothed gears fisandlllvarranged within the. bozo I, The; ends of the tubular conductors 6, l5, "Mend l I. enclosing the].cable.entering theo gear box- I aresecured in these bushings;

Rotatablykmounted'in a journalopeningin the gear box section :I 8 ,is ,theugear Wheel fi the perimeterof which is formed -WithntheH-teethv 4 to meshlwith .the;spaced turns 01E thespirally. wound Aflbevel gear. 23 l is formed on or secured: to! the inward f aceofi the geanwheel 5.

The gear: wheel 21% similar toitheY-gear. wheel 5 is rotatably mounted in2a.journal-topeninginrthe sectionrl 9 of the gear-box" I andritsvaxis:isi-azligned with the axiscofwthetgean E-tWThesgear. z hhas formed-ton .or secured to theinwardifacer-ar-bevel gear '25'rsimi1a-r1 topthegear- 23a Thei journa l orificet 0t thagearrZA- is formed withrlongitudi-nal 1 keyways '24".

-A-spind1e 2641samounted;axiallwtarotatewithin the gear Wheels 5 and 24 and one end of same is formed with a squared portion 21 adapted to fit into and interlock with the squared orifice extendin through a bushin 28 mounted thereon. This bushing is splined externally for part of its length to engage a splined orifice in the gear 24 to rotate same but the splines do not extend the full length of the bushing, consequently when the bushing is reversed and the unsplined end is inserted in the gear, said gear will turn independent of the bushing.

Extending transversely through or otherwise secured to the spindle 26 is a cross spindle 29 arranged midway between the inward faces of the bevel gears 23 and and pinions 30 and 3| which are journalled on the ends thereof are in constant mesh With the said bevel gears.

It will be understood that the cable 2 is looped around each of the gears 5 and 24 and it will be apparent that the rotation of the spindle 26 will, through its transverse spindle 29 and the pinions intermeshing with the bevel gears carried by the gears 5 and 2 5, rotate both gears simultaneously and as these gears rotate they simultaneously apply tension to the section of the cable entering the gear box and compression to the section leaving the gear box.

Ordinarily with cable controlled systems both driving gears are attached to :a common shaft and consequently there can be no relative movement between said gears which are applying the driving loads, one pulling and one pushing. With such conditions of load it is important that the length relationship between the cable and the conducting conduits remain fixed so that both tension and compression loads shall be applied to the cable simultaneously.

The cable is necessarily constructed of steel and the conductor conduit will be of an aluminum alloy, brass or similar material having a considerably diiferent co-efiicient of expansion from that of steel.

It will be appreciated that a drop in temperature will result in a greater shortening of the efiective length of the conductor conduit than the cable, consequently the system will be subjected to excessive compression and conversely with a rise of temperature the system will be subjected to excessive strain. These conditions result in very unstable conditions which cause binding or stillness in operation and undesirable variation in operating load.

The present invention by the very simple expedient of introducing into the operating mechanism of a cable control system a differential gear mechanism, immediately relieves the excess tension or compression through the ability of the driving gears to rotate relative to one another so that the excess material in either the cable or the conductor conduit will be compensated for and there will be an equalizedload at all times.

The practical application of this invention will be at once apparent on examination of the graph curves shown in Figures 6 and 7 which illustrate the diilerence in operating load in a difference in temperature range without the use of the auto- :matic differential gear adjustment which the use of the diiierential eliminates.

A further feature of importance is that in the setting'up of a cable control where no differential is used a certain amount of compression is built up due to the fact that it is necessary to use one driving gear to push the full length of cable through the system until it returns to the final driving box and engages in the cable gear therein.

It is impossible to be certain that engagement is not made between the gears and cable with this compression inherent in the cable, with the result that the final driving gear will not operate in tension to the extent intended.

If it is assumed that the desired condition is achieved and that one driving gear does act on the cable to produce compression and the other to produce tension it will however be understood that the length relationship is critical and will be upset by temperature change.

The use of the diiferential driving gear as described automatically ensures equal tension and compression loads to the cable by each of the two driving gears and therefore prevents initial compression from causing an inefiiciently operating system.

In the maintenance of aircraft it is necessary to remove the control cable periodically for inspection purposes and it has been found that considerable manipulation requiring extensive experience is necessary in the previous forms of controls in order to ensure the least possible compression in the control cable but the introduction of the diiferential drive herein described eliminates this delicate and uncertain condition and the cable may be inserted in a simple threading operation and the differential gears automatically adjust the cable to its most efficient operating position.

In assembling the operating cable one end is inserted into the gear box I to mesh with the peripheral teeth of the gear 5. The splined bushing 28 is reversed so that the outer splined surface looks with the splined orifice of the gear 24 and as the bushing is formed with a squared orifice to engage the squared external end of the spindle 21 the spindle and gears are thus locked together and the turning of the crank mounted on the bushing 28 operates the gears 5 and 24 in unison and the cable engaged thereby is drawn into position by the gears and pushed through the conductor tubing. After the cable has been thus located in the conductor tubes the bushing is reversed so that the gear 24 will not be locked to the spindle and it will therefore operate independently of the spindle allowing the differential to operate freely so that when the operator turns the gears any difference in the length of either of the conductor tubes through expansion or contraction will be automatically compensated.

What I claim as my invention is:

1. An equalizer for cable operated controls, comprising the combination with a gear operated cable slidable in an enclosing conduit and controls engaging same intermediate of its length, of a pair of co-axially journalled gears meshing with spaced lengths of cable, and freely rotatable differential means for driving said gears to push or pull said cable lengths and equalize the compression or tension loads applied thereto in operating the controls.

2. In a device as claimed in claim 1, means for locking said differential gear driving means from differential operation to push the cable through the cable conduit under uniform pressure.

3. An equalizer forcable operated controls, comprising the combination with a gear operated cable slidable in an enclosing conduit and controls engaging same intermediate of its length, of a gear casing, cable engaging gears journalled co-axially in said casing and havin bevel gear surfaces facing inwardly, one of said gears having longitudinal keyways in its journal surface, a driving shaft extending through said gears, a spindle mounted transversely of said shaft between said gears, bevel pinions mounted on said spindle and meshing with said bevel gears, a, bushing non-rotatably mounted on said shaft and having longitudinal splines to engage the keyways of said gear to lock said gear to rotate with said shaft, said bushing having one end formed without splines and when reversed to permit the rotation of the spline-engaging gear to turn freely, and a handle secured to said bushing to rotate said bushing and the shaft.

4. In an aeroplane flap control, the combination with jacks for operating said flaps having cable operated gears enclosed in casings, of a conduit connecting said jack gear casings, an operating gear casing, a pair of cable-operating gears coaxially mounted in said operating casing, a conduit extending from one of said jack gear casings to said operating gear casing to direct the cable around one of said gears, a conduit extending from the other of said jack gear casings to said operating gear casings to direct the cable around the other of said operating gears, conduits leading from said operating gearcasing to enclose the ends of said cable, and differential means arranged co-axial with said operating gears for driving said gears in either direction.

WILLIAM H. D. BROUSE.

REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,974,361 La Neve Sept. 18, 1934 FOREIGN PATENTS Number Country Date 510,013 Great Britain July 25, 1939 546,430 Great Britain Jan. 2, 1942 

